Jobs that use HyperText Markup Language (HTML) and Cascading Style Sheets (CSS) include web design and web development positions. You may also use HTML and CSS code in online application and software design. The duties in these positions typically focus on user experience, so you use code to design the structure and style of an application or website. A web designer or developer may focus on a specialty, such as customizing the format of existing frameworks like WordPress. Website testers and quality assurance specialists also need HTML knowledge, as do online media producers and social media specialists.